The invention relates to open-end, ringless weaving machines, and more particularly to arrangements in such machines for initiating a spinning-in procedure upon the occurrence of a yarn breakage or similar malfunction.
In machines of the contemplated type, a set of draw-off rollers are provided for withdrawing spun yarn from the spinning chamber. The yarn is then routed to a traversing distributing roller, which distributes the spun yarn in roving fashion across a take-up bobbin to yield a yarn package thereon whose diameter increases in proportion to the quantity of withdrawn yarn.
Upon the occurrence of yarn breakage or other malfunction, it has been conventional to initiate a spinning-in process whereby the direction of rotation of the draw-off and distributing rollers are reversed. This is provided for by generating a set of adjustment signals, which are respectively applied to the appropriate rollers in timed rotation upon the sensing of the yarn breakage.
The timing relationship between the sensing of the yarn breakage condition and the initiation of the adjustment signals has in the past been chosen in accordance with the characteristic of the spun yarn itself, e.g., its count twist number.
Unfortunately, the dependency of the various delays in the adjustment signals on the characteristics of the yarn do not solve a possibly even more important problem, i.e., the dependency of an optimum spinning-in operation on changes in the diameter of the yarn package on the take-up bobbin as the winding operation proceeds. As a result, the initiation of the spinning-in operation has been adversely effected because of significant changes in friction between the bobbin and the traversing distributing roller as the yarn package builds up on the bobbin. In addition, the initiation of the spinning-in operation has suffered because of changes in the moment of inertia and other dynamic effects of the rollers and bobbin as the yarn package diameter increases.